They all got to attack him. He was the easy target. He diverted them from attacking each other - except Bernie. And that's the point isn't it? If not for Bloomberg, they'd have been either attacking Bernie or each other. And they don't want to attack each other at this stage any more than necessary because it will take all four of them - Warren, Biden, Buttigieg and Klobacher - to divide up the vote and allow the DNC to invoke the super delegates to steal the election from Bernie.